The current House proposal, from Reps. Darrell Issa (R-Calif.) and Dennis Ross (R-Fla.), is vastly different from the Senate bill, meaning a conference committee would likely be needed to reconcile the two chambers’ legislation.

USPS, which faces a decline in first-class mail volume, lost roughly $5.1 billion in fiscal 2011, and has said it needs to cut $22.5 billion from its annual ledger by 2016.

The agency has also said that it will not be able to make roughly $11 billion worth of prepayments for retiree healthcare that are due in August and September.

Postmaster General Patrick Donahoe has also urged Congress to pass postal legislation as quickly as it can.

But GOP aides on Capitol Hill have said that the Senate bill falls short, and that they are trying to ensure that the House bill restores USPS to long-term solvency once and for all.

Still, there is also speculation that House Republicans don’t yet have the votes to pass their plan.

The Senate bill would, among other things, allow USPS to use an overpayment into a federal pension plan to incentivize workers into retirement, and offer relief to the healthcare prepayment.

Meanwhile, the current House proposal would allow the Postal Service to move more quickly to scrap Saturday delivery than the Senate bill, and would empower an oversight commission to consolidate costs.

Carper has already unveiled a page on his site that tracks postal losses since the Senate passed its bill.